Evaluation of Largemouth Bass Length Limits and Catch-and-Release Regulations, with Emphasis on the Incorporation of Biologists' Perceptions of Largemouth Bass Length Frequency Distributions

Abstract

A survey of fisheries biologists was used to assess changes in size structure of populations of largemouth bass Micropterus salmoides in relation to additional harvest regulations and to associate biologists' perceptions with various measures of length frequency changes. Biologists were presented with largemouth bass population data from regulated and control fisheries and then were asked to judge whether they perceived that the population size structure had improved over time. A blind survey approach was used (biologists did not know which populations received the additional regulations or which were control fisheries). We developed statistical models that include lake, regulation type, and biologist effects and compared them with traditional statistical analyses of regulation effectiveness. Based on perceptions of fisheries biologists about length frequency changes, 12-in maximum length limits and catch-and-release regulations were about four times more likely to improve the size structure than just reliance on standard bag limits (the regulation on control fisheries). Improvement in size structure substantially beyond a statistically significant change was often needed before a regulation was considered successful by fisheries biologists. Individuals differed in their propensity to see changes as improvements. The advantages and caveats of using biologists' perceptions as a component of regulation analyses were discussed. A similar approach using angler questionnaires may yield informative data on what constitutes an improved fishery.